We also take the Cincy/Villages drive - and it depends on the size of your dog. Most of the Motels don't mind the little dogs, but, you pay extra for over 25#. We just dont tell them.
Best Red Roof is the one in Marietta - about 1/2 way. It is fairly new - and we thought it was nice.
Below is a good link for you - pet friendly hotels along I75
http://www.dogfriendly.com/server/tr...y/i75aUS.shtml
One that I do not recommend is in Chattanooga.
Also the LaQuinta is nice - and they take dogs free.